Brendan Dassey's brother has come up against the prosecutor who sent his brother and Steven Avery to jail, calling him a "sweaty ass."

Brad Dassey revealed his anger towards Ken Kratz, who led the case against Steven and Brendan, leading to their being locked up for life, with only Brendan being allowed parole in 2048 at the earliest.

The pair were followed in the Netflix documentary Making A Murderer, which looked into the murder of Teresa Halbach in 2005, when she was killed and her corpse was mutilated.

Now Brad has spoken out against the prosecutor who sent his brother and Steven to prison for the murder.

He told The Daily Star : "I think Ken should shut his damn mouth because nobody likes him. We're sick of hearing from him and his sweaty ass.

Brendan Dassey with Barbara and Scott Tadych (Image: Netflix)

“I can't wait until the day Kathleen Zellner takes him down. I personally don't think he should have paraded his sweaty ass all over local TV back then before the trial even happened.

"In my eyes, it was guilty until proven innocent.”

Steven was given a life sentence with no possibility of parole for the murder, but acquitted of the charge about the corpse's mutilation, while Brendan was convicted of murder, rape, and mutilation in a separate trial, being given a life sentence despite being only 17 years of age at the time.

Steven had served 18 years for attempted murder and was released two years before Teresa's murder after being exonerated.

Brad Dassey (Image: Netflix)

In the latest series of the show, an alternative suspect has been brought forward - Brendan's brother Bobby - after child pornography and necrophiliac content was found on the family computer after he had downloaded it.

Brad has claimed that Bobby and Brendan's mother, Barb Tadych, who was formerly Brad's stepmum, asked him to fix the computer after it had been wiped, though he refused.

He explained further family dramas which have meant he is not speaking to Brendan or Barb at present.

Brad continued: "There's been some family drama going on. I tried to make peace with the family, but I don't think they really want to reconcile at this time. My brother [Brendan] did write a letter to me recently and said he does still love me. So that's good.

Steven Avery with his parents (Image: Netflix)

"Since Brendan won't write back, I've sent several other loyal supporters little titbits of supportive messages – such as ‘Merry Christmas’, ‘I love you’, ‘Please write back someday’, ‘I’m fighting and praying for you’.’I’m also supporting you any way I can’.”

Brad has recently released a song in support of his brother and Steven, called They Didn't Do It, which was inspired by a leter Brendan wrote to the judge to protest his innocence.